Password Reset - CentOS 7/8/9

How to Reset Root Password on CentOS 7/8/9

If you’ve lost or forgotten your root password on CentOS, you can reset it using IPMI and the GRUB bootloader.

This guide will walk you through the process step-by-step.

Prerequisites

• IPMI access to your server
• CentOS 7, 8, or 9 ISO (for rescue boot if required)
• Basic familiarity with Linux command-line

Step 1: Connect to the IPMI

You will need to access your server’s IPMI interface to perform the reset. Refer to our guide on how to connect to IPMI: How to Access Your Dedicated Server via IPMI

Alternatively, you can download and use IPMIView from Supermicro: Download IPMIView

Step 2: Mount the ISO via IPMI

Booting your server into rescue mode by mounting the CentOS ISO. Refer to our guide here: How to Mount ISO via IPMI Management Web Interface

Step 3: Reboot and Access GRUB Menu

1. If your system is currently running, reboot it via IPMI.
2. When the GRUB boot menu appears, highlight the first boot entry.
3. Press e to edit the selected entry.

Step 4: Edit the Kernel Boot Parameters

1. In the GRUB editor, find the line starting with: linux16
2. Navigate to the end of the line.
3. Add:

(Ensure there is a space before rd.break)

Example: linux16 /vmlinuz-3.10.0-327.28.3.el7.x86_64 root=UUID=xxxx ro crashkernel=auto rhgb quiet LANG=en_US.UTF-8 rd.break

Step 5: Boot into Emergency Mode

• Press Ctrl + X to boot with the modified parameters.
• The system will boot into the initramfs prompt with a root shell.

Step 6: Remount the Root Filesystem with Write Permissions

By default, the root filesystem is mounted as read-only at /sysroot.

Remount it as read/write:

Step 7: Enter chroot Environment

Change root into /sysroot so that commands affect the actual system:

Step 8: Reset the Root Password

Run the passwd command:

Enter your new password twice when prompted.

Step 9: Update SELinux Relabel Timestamp

To ensure SELinux relabels the filesystem properly:

Step 10: Exit and Reboot

1.Exit the chroot environment:

2.Exit the initramfs shell:

The system will now reboot.

Step 11: Log In with the New Password

Once the system boots, you can log in as root using the new password.

You have successfully reset your CentOS root password.